Laminated electronic component and method for manufacturing the same

ABSTRACT

A laminated electronic component is configured to include substrate plating films disposed on outer surfaces of an electronic component main body through direct plating such that external terminal electrodes are connected to exposed portions of internal conductors (internal electrodes), and the average particle diameter of metal particles defining the substrate plating film is at least about 1.0 μm. The external terminal electrode includes at least one layer of an upper plating film disposed on the substrate plating film. The metal particles defining the substrate plating film are Cu particles.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a laminated electronic component and amethod for manufacturing the same. In particular, the present inventionrelates to a laminated electronic component in which external terminalelectrodes connected to internal conductors are formed on outer surfacesof an electronic component main body through a direct plating step and amethod for manufacturing the same.

2. Description of the Related Art

In recent years, the market for small portable electronic equipment,e.g., cellular phones, notebook personal computers, digital cameras, anddigital audio equipment, has been increasing. In the portable electronicequipment, miniaturization has been advanced which, at the same time,performance has been improved. A plurality of laminated electroniccomponents are mounted on the portable electronic equipment, andminiaturization and performance enhancement of these laminatedelectronic components have also been required. For example,miniaturization and an increase in capacity are required for laminatedceramic capacitors.

To achieve the miniaturization and increase the capacity of thelaminated ceramic capacitor, it is useful to reduce the thickness of aceramic layer. Recently, a capacitor in which the thickness of ceramiclayer is about 3 μm or less has been used. At present, furtherreductions in thickness are required. However, there is a problem inthat as the thickness of the ceramic layer is reduced, short-circuitingbetween internal electrodes readily occurs and, thereby, it is difficultto ensure quality.

It is also effective to increase an effective area of the internalelectrode. However, in mass production of the laminated ceramiccapacitor, it is necessary to provide a side margin between an internalelectrode and a side surface of a ceramic element assembly and an endmargin between the internal electrode and the end surface of the ceramicelement assembly due to deviations in lamination and deviations incutting of the ceramic green sheets. Therefore, when an increase in theeffective area of the internal electrode is desired, it is necessarythat the area of the ceramic layer is increased in order to provide apredetermined margin. However, there is a limit to the amount ofincrease in the area of the ceramic layer within the bounds of adimensional standard of the product. Furthermore, the thickness of theexternal terminal electrode prevent an increase in the area of theceramic layer.

Previously, the external terminal electrode of the laminated ceramiccapacitor is formed by applying an electrically conductive paste to anend portion of a ceramic element assembly and baking the ceramic elementassembly. As the method for applying the electrically conductive paste,a method in which the end portion of the ceramic element assembly isimmersed in a paste bath and is removed therefrom is conventionallyused. However, in this method, the electrically conductive paste tendsto predominantly adhere to a center portion of the end surface of theceramic element assembly due to the influence of the viscosity of theelectrically conductive paste. Consequently, the external terminalelectrode becomes thick at portions thereof (specifically, greater than30 μm, for example), and the area of the ceramic layer has to be reducedaccordingly.

Under the circumstances, a method has been proposed in which an externalterminal electrode is formed by direct plating. According to thismethod, a plating film is deposited while an exposed portion of aninternal electrode exposed at an end surface of a ceramic elementassembly functions as a seed, and exposed portions of adjacent internalelectrodes are connected to each other through growth of the platingfilm. According to this method, a thin, flat electrode film can beformed as compared to that formed by using the electrically conductivepaste according to a method of the related art (see, for example,International Patent Publication WO 2007/049456).

However, when the external terminal electrode is formed through directplating on an outer surface of the electronic component main body(ceramic element assembly), since the thickness of the plating film isrelatively small, an intrusion path of moisture and other contaminantsfrom the outside becomes short and, thereby, there is a problem in thatthe reliability in moisture-resistance at high temperatures isdeteriorated.

SUMMARY OF THE INVENTION

To overcome the problems described above, preferred embodiments of thepresent invention provide a laminated electronic component includingexternal terminal electrodes formed on outer surfaces of an electroniccomponent main body by direct plating and which has outstanding moistureresistance and a method for manufacturing the same.

A laminated electronic component according to a preferred embodiment ofthe present invention includes an electronic component main bodyincluding a plurality of laminated functional layers, internalconductors which are disposed inside the electronic component main bodyand which have exposed portions exposed at outer surfaces of theelectronic component main body, and external terminal electrodesdisposed on the outer surfaces of the electronic component main body soas to connect the internal conductors and cover the exposed portions ofthe internal conductors, wherein the external terminal electrodeincludes a substrate plating film disposed on the outer surface of theelectronic component main body by direct plating so as to cover theexposed portions of the internal conductors, and the average particlediameter of metal particles defining the substrate plating film is atleast about 1.0 μm.

Preferably, the external terminal electrode further includes at leastone upper plating film layer disposed on the substrate plating film.

Preferably, the metal particles defining the substrate plating film areCu particles.

A method for manufacturing a laminated electronic component including anelectronic component main body including a plurality of laminatedfunctional layers, internal conductors which are disposed inside theelectronic component main body and a portion of which are exposedportions exposed at outer surfaces of the electronic component mainbody, and external terminal electrodes disposed on the outer surfaces ofthe electronic component main body so as to connect to the internalconductors and cover the exposed portions of the internal conductors,according to a preferred embodiment of the present invention, includesthe step of forming a substrate plating film having an average particlediameter of metal particles of at least about 1.0 μm on the outersurface of the electronic component main body through direct plating soas to cover the exposed portions of the internal conductors in theformation of the external terminal electrodes on the electroniccomponent main body.

Preferably, in the laminated electronic component including theelectronic component main body in which the plurality of functionallayers are laminated, the internal conductors which are disposed in theinside of the electronic component main body and a portion of which areexposed portions exposed at the outer surfaces of the electroniccomponent main body, and the external terminal electrodes disposed so asto connect to the internal conductors and cover the exposed portions ofthe internal conductors, the external terminal electrode includes thesubstrate plating film disposed on the outer surface of the electroniccomponent main body through direct plating so as to cover the exposedportions of the internal conductors, and the average particle diameterof metal particles defining the substrate plating film is at least about1.0 μm. Consequently, moisture intrusion paths are reduced and theintrusion of moisture from the outside is prevented. As a result,moisture resistance of the laminated electronic component can be greatlyimproved. That is, moisture intrusion paths formed at grain boundariesare reduced by specifying the average particle diameter of metalparticles to be at least about 1.0 μm and, thereby, the moistureresistance can be improved as compared to a case in which the averageparticle diameter is less than about 1.0 μm.

The substrate plating film can be formed by a method in which thesurface of the electronic component main body is subjected to strikeplating and, thereafter, a plating film having an average particlediameter of metal particles of at least about 1.0 μm is formed, a methodin which a strike plating film having an average particle diameter ofmetal particles of at least about 1.0 μm is formed on the surface of theelectronic component main body and the strike plating film defines asubstrate plating film on an as-is basis, or a method in which thesurface of the electronic component main body is subjected to apretreatment and, thereafter, a plating film is directly formed suchthat the average particle diameter of metal particles is at least about1.0 μm. However, the method for forming the substrate plating film isnot specifically limited.

Furthermore, when at least one layer of upper plating film is disposedon the substrate plating film, the external terminal electrode can beprovided with preferable characteristics in addition to the moistureresistance by appropriately selecting the type of the upper plating filmand combining the upper plating film with the substrate plating film,such that a laminated electronic component having further improvedcharacteristics can be obtained.

For example, a Cu plating film having an average particle diameter ofmetal particles of at least about 1.0 μm is formed as the substrateplating film, a Ni plating film is formed thereon, a Sn plating film isfurther formed on the Ni plating film and, thereby, a laminatedelectronic component provided with external electrodes havingoutstanding characteristics can be obtained, wherein the substrateplating film performs a moisture-resisting function, the Ni plating filmperforms a solder-barrier function, and Sn plating film performs afunction of ensuring wettability.

Usually, as the material for a plating film defining an outermost layerof the upper plating film, an appropriate metal material is selected inaccordance with a mounting arrangement. For example, when the laminatedelectronic component is mounted using soldering, Sn may preferably beused, when the laminated electronic component is mounted using wirebonding, Au may preferably be used, and when the laminated electroniccomponent is embedded in a substrate, Cu may preferably be used.

In various preferred embodiments of the present invention, it ispreferable that the metal particles defining the substrate plating filmare Cu particles, for example. This is because, for example, the filmformability is improved (stretchable), the oxidation resistance isexcellent, the bondability of the internal electrode is good (inparticular, diffusibility with Ni is good), and the density isrelatively high (recrystallization temperature is low).

In the method for manufacturing a laminated electronic componentaccording to various preferred embodiments of the present invention, thesubstrate plating film having an average particle diameter of metalparticles of at least about 1.0 μm is formed by direct plating on theouter surface of the electronic component main body so as to cover theexposed portions of the internal conductors during the formation of theexternal terminal electrodes on the electronic component main body.Consequently, moisture intrusion paths formed at grain boundaries arereduced and, thereby, the intrusion of moisture is suppressed. As aresult, the reliability in moisture resistance of the laminatedelectronic component can be greatly improved.

Other features, elements, characteristics and advantages of the presentinvention will become more apparent from the following detaileddescription of preferred embodiments of the present invention withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an external configuration of alaminated electronic component according to a first preferred embodimentof the present invention.

FIG. 2 is a sectional view of a section taken along a line II-II shownin FIG. 1.

FIG. 3 is a diagram showing internal electrode patterns of the laminatedceramic capacitor according to the first preferred embodiment of thepresent invention.

FIG. 4 is a diagram showing a magnified portion of the laminated ceramiccapacitor according to the first preferred embodiment of the presentinvention.

FIG. 5 is a diagram showing a magnified portion of a laminated ceramiccapacitor according to a second preferred embodiment of the presentinvention.

FIG. 6 is a sectional view showing a configuration of a laminatedceramic capacitor according to a third preferred embodiment of thepresent invention.

FIG. 7 is a perspective view showing an external configuration of anarray type laminated ceramic capacitor (capacitor array) according to afourth preferred embodiment of the present invention.

FIG. 8 is a diagram showing an arrangement pattern of a plurality ofinternal electrodes in the array type laminated ceramic capacitoraccording to the fourth preferred embodiment of the present invention.

FIG. 9 is a diagram showing a multiterminal type low ESL laminatedceramic capacitor according to a fifth preferred embodiment of thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The features of the present invention will be described below in furtherdetail with reference to preferred embodiments of the present invention.

First Preferred Embodiment

In the first preferred embodiment of the present invention, atwo-terminal type laminated ceramic capacitor including a pair ofexternal terminal electrodes defined by one Cu plating film layer willbe described as an example of a laminated electronic component.

FIG. 1 is a perspective view showing an external configuration of alaminated ceramic capacitor according to the first preferred embodimentof the present invention. FIG. 2 is a sectional view of a section takenalong a line II-II shown in FIG. 1. FIG. 3 is a diagram showing internalelectrode patterns of this laminated ceramic capacitor. FIG. 4 is adiagram showing a magnified portion, e.g., a connection portion betweenan external terminal electrode and an internal electrode.

The laminated ceramic capacitor includes a capacitor main body 10 in theshape of a substantially rectangular parallelepiped having a firstprincipal surface 11 and a second principal surface 12 that are oppositeto each other, a first side surface 21 and a second side surface 22 thatare opposite to each other, and a first end surface 31 and a second endsurface 32 that are opposite to each other. The capacitor main body 10includes a plurality of laminated dielectric layers 50.

A first external terminal electrode 1 is disposed on the first endsurface 31, and a second external terminal electrode 2 is disposed on asecond end surface 32. The first external terminal electrode 1 and thesecond external terminal electrode 2 are electrically insulated fromeach other.

First surface conductors 13 and second surface conductors 14 aredisposed on the first principal surface 11 and the second principalsurface 12, respectively. The first surface conductors 13 are arrangedat folded portions of the first external terminal electrode 1, and thesecond surface conductors 14 are arranged at folded portions of thesecond external terminal electrode 2. The first and the second surfaceconductors 13 and 14 may also be provided on the first side surface 21and the second side surface 22. When the folded portions of the firstand the second external terminal electrodes 1 and 2 are not required tobe relatively long, the first and the second surface conductors 13 and14 need not be provided.

As shown in FIG. 2, first internal electrodes 41 and second internalelectrodes 42 are arranged to face each other with dielectric layers 50disposed therebetween inside the capacitor main body 10. As shown inFIG. 3, the first internal electrode 41 extends to the first end surface31 and is electrically connected to the first external terminalelectrode 1. The second internal electrode 42 extends to the second endsurface 32 and is electrically connected to the second external terminalelectrode 2.

As shown in FIG. 4, the first external terminal electrode 1 (secondexternal terminal electrode 2) includes a substrate plating film 1 a (2a) defined by a Cu plating film, a first upper plating film 1 b (2 b)defined by a Ni plating film, and a second upper plating film 1 c (2 c)defined by a Sn plating film.

In FIG. 4, a connection portion between the first external terminalelectrode 1 disposed on the first end surface of the capacitor main body10 and the first internal electrode 41 is shown. On the other hand, aconnection portion between the second external terminal electrode 2(refer to FIGS. 1 and 2) and the second internal electrode 42 and theconnection portion shown in FIG. 4 are mirror images of each other.Therefore, the substrate plating film 2 a, the first upper plating film2 b, the second upper plating film 2 c, and the second internalelectrode defining the second external terminal electrode 2 are shown inparentheses.

As shown in FIG. 4, the external terminal electrode 1 (2) of thelaminated ceramic capacitor of the first preferred embodiment preferablyhas a three-layer structure including the substrate plating film 1 a (2a), the first upper plating film 1 b (2 b), and the second upper platingfilm 1 c (2 c), for example.

The average particle diameter of metal particles defining the substrateplating film 1 a (2 a) preferably is at least about 1.0 μm, for example.

In the first preferred embodiment, the substrate plating film 1 a (2 a)is made of a Cu strike plating film provided directly on the end surface31 (32) of the capacitor main body 10 and a thick Cu plating filmdisposed thereon. However, the substrate plating film 1 a (2 a) canpreferably be disposed directly on the end surface of the capacitor mainbody 10 not provided with the Cu strike plating film, or may preferablyinclude only the Cu strike plating film.

Preferably, the substrate plating film and the upper plating film areformed from, for example, a plating film of one type of metal selectedfrom the group consisting of Cu, Ni, Sn, Pb, Au, Ag, Pd, Bi, and Zn oran alloy containing the above-described metal.

In the laminated ceramic capacitor of the first preferred embodiment,the substrate plating film 1 a (2 a) defined by a Cu plating filmensures the sealing performance so as to prevent intrusion of moistureand other contaminants from the outside.

The first upper plating film 1 b (2 b) defined by the Ni plating filmprovides the solder-barrier function.

Furthermore, the second upper plating film 1 c (2 c) defined by the Snplating film provides the function of ensuring wettability.

In preferred embodiments of the present invention, the material for theplating film defining the outermost layer of the upper plating film (inthe first preferred embodiment, the second upper plating film 1 c (2 c))is selected in accordance with a mounting arrangement. For example, whena product is mounted using wire bonding, Au can preferably be used, anda product is embedded in a substrate, Cu can preferably be used.

The preferable materials and thicknesses of the dielectric layersdefining the laminated ceramic capacitor, the first and the secondinternal electrodes defining internal conductors, and the externalterminal electrodes will be described below.

Dielectric Layer

For the material defining the dielectric layer, a dielectric ceramicincluding, for example, BaTiO₃, CaTiO₃, SrTiO₃, and CaZrO₃, as a primarycomponent can preferably be used. Alternatively, materials in whichsecondary components, e.g., Mn compounds, Fe compounds, Cr compounds, Cocompounds, and Ni compounds, for example, are added to these primarycomponents may preferably be used.

It is preferable that the thickness of the dielectric layer after firingis about 1 μm to about 10 μm.

Internal Electrode

For the material defining the internal electrode, for example, Ni, Cu,Ag, Pd, Ag—Pd alloys, and Au can preferably be used.

It is preferable that the thickness of the internal electrode afterfiring is about 0.5 μm to about 2.0 μm, for example.

External Terminal Electrode

Preferably, the substrate plating film defining the external terminalelectrode is a plating film made of a metal selected from the groupconsisting of Cu, Ni, Sn, Pb, Au, Ag, Pd. Bi, and Zn or an alloyincluding the metal, for example.

It is preferable that the thickness of the substrate plating film afterfiring is about 1 μm to about 10 μm, for example.

For the material of the upper plating film defining the externalterminal electrode, an appropriate metal material is selected inaccordance with the mounting arrangement.

For example, when the laminated ceramic electronic component is mountedusing soldering, a material, for example, Ni, that is capable providinga solder barrier function and a material, for example, Sn, that iscapable of providing excellent wettability are preferably used.

For example, when the laminated electronic component is mounted usingwire bonding, Au is preferably used, and when the laminated electroniccomponent is embedded in a substrate, Cu is preferably used.

A method for manufacturing the laminated ceramic capacitor of the firstpreferred embodiment will be described below.

(1) Ceramic green sheets and an electrically conductive paste forforming internal electrodes are prepared. The ceramic green sheets andthe electrically conductive paste include a binder and a solvent, andorganic binders and organic solvents in the related art can preferablybe appropriately selected and used.

(2) The electrically conductive paste is printed in predeterminedpatterns on the ceramic green sheets by, for example, screen printing soas to form internal electrode patterns.

(3) Individual ceramic green sheets are laminated in a predeterminedorder such that a predetermined number of ceramic green sheets withprinted internal electrode patterns are laminated, and a predeterminednumber of outer layer ceramic green sheets with no printed internalelectrode pattern nor internal conductor pattern are laminated on thetop and the bottom thereof so as to provide a mother laminate. Ifnecessary, the mother laminate is press-bonded in a lamination directionby an isostatic press or other suitable method.

(4) An unfired mother laminate is cut into a predetermined size so thatan unfired capacitor main body is produced.

(5) The resulting unfired capacitor main body is fired. The firingtemperature depends on the type of ceramic defining the ceramic greensheet and the material used for the internal electrode. Usually, it ispreferable that the firing is conducted at about 900° C. to about 1,300°C., for example.

(6) If necessary, a polishing treatment, e.g., barrel finishing, isperformed on the exposed portion of the internal electrode. At thistime, chamfering is also performed so as to round the ridge and thecorner portion of the capacitor main body. Furthermore, if necessary,water repellent finishing is performed and, thereby, a pretreatment toprevent the intrusion of the plating solution in gaps between theexposed portion of the internal electrode and the dielectric layer isperformed.

(7) The capacitor main body is subjected to a plating treatment, sothat, as shown in FIG. 4, metal particles are deposited on the exposedportions of the first internal electrodes 41 and the second internalelectrodes 42 and, thereby, the substrate plating films 1 a and 2 a areformed.

When the first surface conductors 13 and the second surface conductors14 (refer to FIG. 2) are formed, the surface conductor patterns may beprinted on the outermost ceramic green sheets in advance and co-firingmay be performed together with the ceramic element assembly.Alternatively, the surface conductors may be printed on the principalsurfaces of the ceramic element assembly after firing and, thereafter,baking may be performed.

For the formation of the substrate plating films 1 a and 2 a, Cu strikeplating films are formed directly on the end surfaces of the capacitormain body 10, and thick Cu plating is performed thereon by Cuelectroplating so as to form the substrate plating films 1 a and 2 a. Atthis time, the average particle diameters of Cu particles of the thickCu plating films, which are the main bodies of the substrate platingfilms 1 a and 2 a, are preferably set to be at least about 1.0 μm, forexample.

Here, after the Cu strike plating film is formed, the thick Cu platingis applied thereto and, thereby, the substrate plating film 1 a or 2 ais formed. However, in some cases, the substrate plating film can beformed by applying the thick Cu plating to the end surface of thecapacitor main body without forming the Cu strike plating film.

Furthermore, in some cases, the substrate plating films 1 a and 2 a canbe formed of only the Cu strike plating films.

Intrusion of moisture into the capacitor main body can be reliablyprevented or prevented preferably by specifying the average particlediameter of the Cu particles defining the substrate plating film (thickCu plating film) to be at least about 1.0 μm, for example, as in thefirst preferred embodiment.

The average particle diameter of the Cu particles defining theabove-described Cu strike plating film is not specifically limited.However, the average particle diameter of the Cu strike plating film maypreferably be set to at least about 1.0 μm and, thereby, the averageparticle diameter of the Cu particles in the entire substrate platingfilm may preferably be set to at least about 1.0 μm.

(8) Subsequently, Ni electroplating and Sn electroplating are furtherperformed, so that the first upper plating layer 1 b (2 b) defined bythe Ni plating film and the second upper plating layer 1 c (2 c) definedby the Sn plating film are formed.

In this manner, the laminated ceramic capacitor shown in FIG. 1 and FIG.2 can be obtained. As for the plating, either electroplating orelectroless plating may be used. However, usually, it is preferable thatthe electroplating is used because in the case in which an increase inplating deposition rate is desired in the electroless plating, apretreatment with a catalyst is required and, therefore, the processbecomes complicated.

Furthermore, as for the plating method, for example, it is preferablethat barrel plating, in which the capacitor main body is disposed in abarrel and plating is performed while the barrel is rotated, is used,although other methods can also be used.

Second Preferred Embodiment

FIG. 5 is a diagram showing a magnified portion of a laminated ceramiccapacitor according to a second preferred embodiment of the presentinvention. The configurations and materials of the laminated ceramiccapacitor according to the second preferred embodiment are substantiallythe same as those in the laminated ceramic capacitor according to thefirst preferred embodiment except that the first (and the second)external terminal electrode 1 (2) includes only the substrate platingfilm 1 a (2 a).

FIG. 5 shows a connection portion between the first external terminalelectrode 1 disposed on the first end surface 31 of the capacitor mainbody 10 and the first internal electrode 41. On the other hand, aconnection portion between the second external terminal electrode 2(refer to FIGS. 1 and 2) and the second internal electrodes 42 and theconnection portion shown in FIG. 5 are mirror images of each other.Therefore, the substrate plating film 2 a and the second internalelectrode 42 defining the second external terminal electrode 2 are shownin parentheses.

The laminated ceramic capacitor according to the second preferredembodiment can be produced by a method similar to the method formanufacturing the laminated ceramic capacitor according to the firstpreferred embodiment.

However, in the step of forming the external terminal electrode, thestep of forming the upper plating film on the substrate plating film isomitted.

Third Preferred Embodiment

FIG. 6 is a diagram showing a laminated ceramic capacitor according to athird preferred embodiment of the present invention. The laminatedceramic capacitor according to the third preferred embodiment hassubstantially the same configuration as that of the laminated ceramiccapacitor according to the first embodiment except that the capacitormain body 10 includes dummy internal electrodes D (D₁, D₂). In FIG. 6,the same portions as or the portions corresponding to those shown inFIG. 2 are indicated by the same reference numerals as those set forthabove.

For dummy electrodes D in the laminated ceramic capacitor, first dummyinternal electrodes D₁ that extend to the first end surface 31 andsecond dummy internal electrodes D₂ that extend to the second endsurface 32 are provided. The first dummy electrodes D₁ and the seconddummy electrodes D₂ are disposed on the same or substantially the sameplanes as those on which the individual internal electrodes 41 and 42between the dielectric layers 50 are disposed, and are also disposed inouter layer portions, in which no internal electrode is disposed,outside the region in which the internal electrodes are disposed in alamination direction.

The laminated ceramic capacitor according to the third preferredembodiment can also be produced by a method similar to the method formanufacturing the laminated ceramic capacitor according to the firstpreferred embodiment.

In the case in which the laminated ceramic capacitor according to thethird preferred embodiment is produced, ceramic green sheets definingfunctional layer portions which are provided with internal electrodepatterns and dummy internal electrode patterns and ceramic green sheetsdefining outer layer portions which are provided with only dummyinternal electrode patterns are prepared as required, and are laminatedin a predetermined order. It is also possible that ceramic green sheetsprovided with neither internal electrode pattern nor dummy internalelectrode pattern are provided.

Fourth Preferred Embodiment

FIG. 7 is a diagram showing an array type laminated ceramic capacitor(capacitor array) according to a fourth preferred embodiment of thepresent invention. FIG. 8 is a diagram showing an arrangement pattern ofinternal electrodes. As shown in FIG. 7, the array type laminatedceramic capacitor according to the fourth preferred embodiment includesa capacitor array main body 10A substantially in the shape of arectangular parallelepiped having a first principal surface 11 and asecond principal surface 12 opposite thereto, a first side surface 21and a second side surface 22 opposite to thereto, and a first endsurface 31 and a second end surface 32 opposite thereto.

A plurality of first external terminal electrodes 101 is disposed on thefirst end surface 31 of the capacitor array main body 10A, and aplurality of second external terminal electrode 102 is disposed on thesecond end surface 32. The first external terminal electrodes 101 andthe second external terminal electrodes 102 are electrically insulatedfrom each other.

As shown in FIG. 8, a plurality of first internal electrodes 141 a, 141b, 141 c, and 141 d and a plurality of second internal electrodes 142 a,142 b, 142 c, and 142 d are provided with dielectric layers 50therebetween in the capacitor array main body 10A. That is, with respectto one plane, the first internal electrodes 141 a, 141 b, 141 c, and 141d and the second internal electrodes 142 a, 142 b, 142 c, and 142 d arealternately arranged along a longitudinal direction of the capacitorarray main body 10A, and with respect to the lamination direction, thefirst internal electrodes 141 and the second internal electrodes 142 arearranged so as to be opposed to each other with dielectric layers 50therebetween. Furthermore, as shown in FIG. 8, the individual firstinternal electrodes 141 a, 141 b, 141 c, and 141 d extend to the firstend surface 31 and are electrically connected to the first externalterminal electrode 101. The second internal electrodes 142 a, 142 b, 142c, and 142 d extend to the second end surface 32 and are electricallyconnected to the second external terminal electrode 102.

In this array type laminated ceramic capacitor according to the fourthpreferred embodiment, four capacitor portions C1, C2, C3, and C4 definedby opposing the individual first internal electrodes 141 to theindividual second internal electrodes 142 with the dielectric layers 50therebetween are disposed along the longitudinal direction of thecapacitor array main body 10A.

In this array type laminated ceramic capacitor according to the fourthpreferred embodiment, the individual external terminal electrodes havethe same or substantially the same configurations as those in the firstpreferred embodiment and are provided with a substrate plating film andan upper plating film including a first upper plating film defined by aNi plating film and a second upper plating film defined by a Sn platingfilm.

The laminated ceramic capacitor according to the fourth preferredembodiment can also be produced by a method similar to the method formanufacturing the laminated ceramic capacitor according to the firstpreferred embodiment. However, it is necessary that, for example,ceramic green sheets provided with internal electrode patterns inaccordance with the shape of the internal electrodes are used and theexternal terminal electrodes are arranged on outer surfaces of thecapacitor array main body so as to cover individual exposed portions ofthe individual internal electrodes.

Fifth Preferred Embodiment

FIG. 9 is a diagram showing internal electrode patterns of amultiterminal type low ESL laminated ceramic capacitor according to afifth preferred embodiment of the present invention.

In the laminated ceramic capacitor according to the fifth preferredembodiment, a first internal electrode 41 has a plurality of leadportions 41 a, 41 b, 41 c, and 41 d, and a second internal electrode 42has a plurality of (in the fifth preferred embodiment, four) leadportions 42 a, 42 b, 42 c, and 42 d. In the fifth preferred embodiment,preferably, the first internal electrode 41 includes four lead portionsand the second internal electrode 42 includes four lead portions, forexample.

As shown in FIG. 9, in each of a first side surface 21 and a second sidesurface 22, the lead portions 41 a, 41 b, 41 c, and 41 d of the firstinternal electrode 41 and the lead portions 42 a, 42 b, 42 c, and 42 dof the second internal electrode 42 are arranged so as to engage witheach other, when viewed from above,

(a) one lead portion 41 b of the first internal electrode 41 is arrangedbetween the lead portions 42 a and 42 b of the second internal electrode42,

(b) another lead portion 41 c of the first internal electrode 41 isarranged between the lead portions 42 c and 42 d of the second internalelectrode 42,

(c) one lead portion 42 a of the second internal electrode 42 isarranged between the lead portions 41 a and 41 b of the first internalelectrode 41, and

(d) another lead portion 42 d of the second internal electrode 42 isarranged between the lead portions 41 c and 41 d of the first internalelectrode 41.

In the laminated ceramic capacitor according to the fifth preferredembodiment, although not specifically shown in FIG. 9, the externalterminal electrodes are configured to cover the lead portions (exposedportions) of the first and the second internal electrodes, the leadportions being exposed at the side surfaces of the capacitor main body.

In the laminated ceramic capacitor according to the fifth preferredembodiment, the external terminal electrodes may preferably have aconfiguration similar to that in the first preferred embodiment. Thelaminated ceramic capacitor can also be produced by a method similar tothe method for manufacturing the laminated ceramic capacitor accordingto the first preferred embodiment. However, it is necessary that, forexample, ceramic green sheets provided with internal electrode patternsarranged in accordance with the shape of the internal electrodes areused and the external terminal electrodes are arranged on the sidesurfaces of the capacitor main body so as to cover the individualexposed portions of the individual internal electrodes.

EXAMPLE 1

Preferred embodiments of the present invention will be more specificallydescribed below with reference to examples.

A laminated ceramic capacitor having the following configuration wasprepared by a method similar to the method for manufacturing thelaminated ceramic capacitor according to the first preferred embodiment.

1) Dimensions:

-   -   Length: L=2.0 mm,    -   Width: W=1.25 mm,    -   Height: T=1.25 mm

2) Constituent material for dielectric layer: barium titanate baseddielectric ceramic

3) Constituent material for internal electrode: primary component: Ni

4) The number of lamination: 416 layers (thickness of dielectric layer:1.9 μm)

5) Rated voltage: 6.3 V

6) Capacitance: 10 μF

In this regard, external terminal electrodes provided with the followingsubstrate plating film and the upper plating film were formed byperforming direct plating on a capacitor main body, as described below.

Configuration of External Terminal Electrode (a) Substrate Plating Film

A Cu strike plating film and a thick Cu plating film formed by Cuelectroplating thereon are included. The desired thickness of thesubstrate plating film is about 10 μm.

(b) Upper Plating Film

A first upper plating film which is disposed on the substrate platingfilm and which is formed by Ni electroplating and a second upper platingfilm which is disposed on the first upper plating film and which isformed by Sn electroplating are included.

The preferred thickness of the first upper plating film is about 4 μm,and the preferred thickness of the second upper plating film is alsoabout 4 μm.

The formation of the external terminal electrode will be described belowin detail.

Plating Bath (1) Plating Bath Used for Forming Substrate Plating Film

(a) A plating bath under the following condition was used for formingthe Cu strike plating film constituting the substrate plating film.

Copper pyrophosphate: 14 g/L,

Pyrophosphoric acid: 120 g/L

Potassium oxalate: 10 g/L

pH: 8.6

Temperature: 25° C.

(b) A plating bath under the following condition was used for formingthe thick Cu plating film constituting the substrate plating film.

Component of plating bath: PYROBRIGHT PROCESS produced by C.Uyemura &Co., Ltd.

pH: 8.6

Temperature: 55° C.

The amount of 28% aqueous ammonia that was added to the plating bath waschanged as described below and, thereby, Cu plating films havingdifferent average particle diameters of Cu particles defining thesubstrate plating film were formed.

Sample 1 (comparative example): 2.0 ml/L

Sample 2 (comparative example): 1.5 ml/L

Sample 3 (example): 1.0 ml/L

Sample 4 (example): 0.5 ml/L

Sample 5 (example): 0.0 ml/L

(2) Plating Bath for Forming First Upper Plating Film (Ni Plating Film)

(a) For a plating bath for forming the first upper plating film, anickel plating bath (Watts bath) including nickel sulfate, nickelchloride, and boric acid as primary components (weakly acidic simple Nibath) was used.

pH: 4.2

Temperature: 60° C.

(3) Plating Bath for Forming Second Upper Plating Film (Sn Plating Film)

For a plating bath for forming the second upper plating film, thefollowing plating bath was used.

Component of plating bath: Sn-235 produced by Dipsol Chemicals Co., Ltd.

pH: 5.0

Temperature: 33° C.

Plating method, plating condition, and the like

Plating method: horizontally rotational barrel plating

The number of revolution of barrel: 10 rpm

Electrically conductive media dimension: diameter 1.8 mm (electricallyconductive media)

Current density×time

-   -   Cu strike plating: 0.11 A/dm²×60 min    -   (Thick) Cu plating: 0.30 A/dm²×60 min    -   Ni plating: 0.20 A/dm²×60 min    -   Sn plating: 0.10 A/dm²×60 min

In this example, individual plating films are formed by anelectroplating method, however, the method for forming a plating film isnot specifically limited. It is also possible to form plating films, forexample, a Cu electroless plating film, a Ni—P electroless plating film,and a Ni—B electroless plating film) by an electroless plating method.However, when an internal electrode species does not have catalyticactivity in the electroless plating, it is necessary that a catalystactivation treatment is performed.

Samples (laminated ceramic capacitors) 1 to 5 prepared as describedabove were subjected to a high-temperature and high-humidity test (PCBT)so as to examine the reliability of individual Samples.

The PCBT was performed under the condition of about 125° C./95% RH/6.3 V(rated voltage)/72 hr, samples having insulation resistances reduced toabout 1 MΩ or less were counted as defective samples, and a fraction ofdefective samples was calculated based on the following equation.

fraction defective (%)=(the number of samples counted as defectivesamples/the total number of samples)×100

The results thereof are shown in Table 1.

TABLE 1 Average particle Fraction defective diameter of Cu in PCBTparticles of substrate (%)/(the number of plating film defectivesamples/the (μm) number of samples) Sample 1 (comparative 0.5 45/(9/20) example) Sample 2 (comparative 0.7 25/(5/20)  example) Sample 3 (example1.0 0/(0/20) satisfying requirements of the invention) Sample 4 (example1.3 0/(0/20) satisfying requirements of the invention) Sample 5 (example1.8 0/(0/20) satisfying requirements of the invention)

As shown in Table 1, it was determined that with Sample 1 and Sample 2,which were comparative examples, many defective samples were producedduring the test.

On the other hand, the laminated ceramic capacitors of Sample 3, Sample4, and Sample 5, in which the average particle diameters of Cu particlesof the substrate plating films were at least about 1.0 μm and,therefore, which satisfied the requirements of preferred embodiments ofthe present invention, deterioration of the moisture resistance at hightemperatures was not observed. Thus, it was determined that highreliability in moisture resistance was obtained.

In the above-described examples, laminated ceramic capacitors aredescribed. However, the present invention is not limited to thelaminated ceramic capacitors according to the preferred embodiments ofthe present invention and can be applied to various laminated electroniccomponents, e.g., laminated chip inductors and laminated chipthermistors, having structures in which internal conductors are disposedin the electronic component main body and external terminal electrodesare disposed on surfaces of the electronic component main body so as toconnect to the internal conductors.

In the above-described examples, a case in which the material definingthe electronic component main body is a dielectric ceramic is described.However, the material defining the electronic component main body is notlimited to the dielectric ceramic and may be piezoelectric ceramic,semiconductor ceramic, and magnetic ceramic, for example. Furthermore,the material may include a resin.

The present invention is not limited to the above-described preferredembodiments and examples. Various applications and modifications can bemade with respect to the materials of the internal conductor and theexternal terminal electrode, the method for forming the externalterminal electrode, the material, the number of layers, and the formingmethod of the upper plating film defining the external terminalelectrode within the scope of the present invention.

As described above, according to preferred embodiments of the presentinvention, the reliability in moisture resistance of the laminatedelectronic component provided with external terminal electrodes formedthrough direct plating can be improved. Consequently, preferredembodiments of the present invention can be used for various laminatedelectronic components having structures in which internal conductors aredisposed in the electronic component main body and external terminalelectrodes are disposed through direct plating on surfaces of theelectronic component main body in such a way as to connect to theinternal conductors.

While preferred embodiments of the invention have been described above,it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the invention. The scope of the invention, therefore, is to bedetermined solely by the following claims.

1. A laminated electronic component comprising: an electronic componentmain body including a plurality of laminated functional layers; internalconductors disposed inside the electronic component main body andincluding exposed portions exposed at outer surfaces of the electroniccomponent main body; and external terminal electrodes disposed on theouter surfaces of the electronic component main body so as to connect tothe internal conductors and to cover the exposed portions of theinternal conductors; wherein the external terminal electrodes include asubstrate plating film disposed directly on the outer surfaces of theelectronic component main body so as to cover the exposed portions ofthe internal conductors; and an average particle diameter of metalparticles defining the substrate plating film is at least about 1.0 μm.2. The laminated electronic component according to claim 1, wherein theexternal terminal electrodes further comprise at least one layer of anupper plating film disposed on the substrate plating film.
 3. Thelaminated electronic component according to claim 1, wherein the metalparticles defining the substrate plating film are Cu particles.
 4. Amethod for manufacturing a laminated electronic component including anelectronic component main body including a plurality of laminatedfunctional layers, internal conductors which are disposed inside theelectronic component main body and a portion of which are exposed atouter surfaces of the electronic component main body, and externalterminal electrodes disposed on the outer surfaces of the electroniccomponent main body so as to connect to the internal conductors and tocover the exposed portions of the internal conductors, the methodcomprising the step of: forming a substrate plating film having anaverage particle diameter of metal particles of at least about 1.0 μm onthe outer surfaces of the electronic component main body by directplating so as to cover the exposed portions of the internal conductorsand form the external terminal electrodes on the electronic componentmain body.
 5. The method for manufacturing according to claim 4, furthercomprising a step of forming at least one layer of an upper plating filmon the substrate plating film.
 6. The method for manufacturing accordingto claim 4, wherein the metal particles of the substrate plating filmare Cu particles.